Keeldesign under IRC

Hi,

I´m trying to trying to optimize my 31 ft. IOR-boat under IRC & I´m asking what would be the most suitable keelform under that rule. are there any limits how deep the keel should be, to be advantageous measurement wise?

 

Barsa;

The yacht designer who is the national IRC co-ordinator for Australia has told me that he can find no advantage in keel depth under IRC; just go for the keel depth that suits the boat best and (he say) it will be fairly rated.

I have also asked Mark Mills and John Corby about IRC "specials" and they told me that these days, a good production boat is just as competitive as the IRC specials. That means (the production boats like Beneteau 40.7s not being distorted for IRC) there mustn't be much of an advantage to shallow or deep keels.

 

IRC doesnt penalise weight (understatement?) , so make sure your IOR internal ballast weight goes into your new bulb where its most effective , otherwise take the advantage of "losing it" (any old internal lead) for downwind weight advantage.

not sure re Draft

anyone else out there had rating change re Depth of keel ???

 

I do know that all say that IRC does not encourgae tender designs, this may just be weight factoring not depth tho

Whilst I don't doubt that IRC may not put much weighting on the distance your Bulb is slung under the hull, I am sure there must be some difference !!!!

Ok test case; is take a Beneteau 40.7, sling the identical bulb 3 foot below hull, and another identical boat sling it 9 feet down.

how is the factor under IRC, favourable to the Deep ( stiffer ! ) boat or the shallow (tender ) vers.